Electrostatic spray gun

Abstract

An electrostatic spray gun comprising a housing (32) for receiving a replaceable collapsible container, a nozzle (39) from which fluid is to be sprayed, squeeze grip mechanism (36, 35, 34) for compressing the container to feed fluid to the nozzle and high voltage contacts (38a, 38b) for applying electrostatic potential to the fluid such that the fluid issues from the nozzle in the form of an electrically charged atomized spray, wherein the nozzle (39) forms or is fed by a resealable delivery valve having inner (11) and outer valve members (12) with fluid fed to a gap between them by the compression of the container, from which gap the fluid emerges to form the spray and the gap being closable, desirably with a wipping, fluid-cleaning action, by relative movement of the members.

We claim: 
     
       1. An electrostatic spray gun comprising: a housing;   a handle adjacent said housing;   a replaceable, collapsible container receivable in said housing;   a nozzle in communication with said container for spraying fluid from said container;   a delivery valve having inner and outer valve members, said valve members being movable relative to one another to form an opening for supplying fluid from the container or to form a seal for preventing escape of fluid from the container;   a squeeze gripping means mounted on said housing for transmitting a compressive force to the container to deliver fluid to said nozzle; and   a high voltage generator for applying electrostatic potential to the fluid such that the fluid emerges from said nozzle in a form of an electrically charged atomized spray.   
     
     
       2. An electrostatic spray gun according to claim 1 wherein said delivery valve further comprises at least one elongated channel having a flow-limiting cross section by which a flow rate of fluid from said container through said nozzle is controlled. 
     
     
       3. An electrostatic spray gun according to claim 2 wherein said elongated channel has an adjustable length for changing flow rate of said fluid out of said nozzle. 
     
     
       4. An electrostatic spray gun according to claim 2 comprising at least two elongated channels having differing cross sections. 
     
     
       5. An electrostatic spray gun according to claim 2 wherein said container comprises a flexible wall having bellows, said container being collapsible by said compressive force applied to a rear portion of the container, said delivery valve being positioned near a front portion of the container when said container is received in said housing. 
     
     
       6. An electrostatic spray gun according to claim 2 wherein said container comprises a flexible wall contained within a rigid sleeve, said fluid being delivered to said nozzle by eversion of said flexible wall. 
     
     
       7. An electrostatic spray gun according to claim 2 wherein a portion of said inner valve member is positioned inside said outer valve member, said inner valve member including a blind tip extending outside of said outer valve member and an aperture in a side of said inner valve member through which fluid in the container enters the delivery valve and emerges around said inner valve member in a space between said inner valve member and said outer valve member, a flow rate of fluid through said nozzle being controlled by relative movement of said inner and outer valve members.